Performance Losses in Rooftop-Mounted PV Modules from Long-Term Environmental Exposure at Las Cruces, New Mexico

摘要

Forty-eight PV modules of four different types were instrumented and tested monthly for 3 years to measure and record the performance effects of environmental exposure. Two modules were removed from each set of 12 as a control and for "initial" characterization. As a secondary goal, the effects of mounting topology (open rack, integrated roof, conventional standoff mount) were also closely monitored. Current-voltage (I-V) curve data were archived and normalized according to accepted methods. The EVA pottant in all modules monitored was discolared to a deep yellow-to-brown color from prior exposures before the monitoring was begun. Modules showing observable performance degradation were removed from their mounts and prepared for in-depth analysis. During the 3-year monitoring period, 4 of the 10 Solarex a-Si modules stopped producing, 3 of the 10 Solarex MIT pc-Si modules lost from 5percent to 10percent efficiency, and 1 Mobil Ra-180 pc-Si module lost about 10percent efficiency. For all of the other modules, a loss of less than 1percent per year was recorded, which included all 10 of the Sovonics P-101 a-Si modules.